Process For the Production of Cyclic Diketones

ABSTRACT

The present invention relates to a process for the preparation of compounds of formula (I), wherein the substituents are as defined in claim  1,  by reacting a compound of formula (II), with a bromine or chlorine source to form a compound of formula (III), wherein X is chlorine or bromine; reacting that compound with water to form the compound of formula (IV), converting that compound, using a compound of formula (V), wherein M +  is the hydrogen cation or an alkali metal ion, alkaline earth metal ion or ammonium ion, into the compound of formula (VI), and treating that compound with a cyanide source in the presence of a base.

The present invention relates to a process for the preparation of cyclic1,3-diketone derivatives carbonylated in the 2-position.

Processes for the preparation of cyclic 1,3-diketones substituted in the2-position by an arylcarbonyl group are described, for example, inWO/0015615, WO 00/37437, WO 01/66522 and WO 01/94339. The compoundsdisclosed therein have herbicidal action.

Those known processes have the disadvantage, however, that certaincyclic 1,3-diketone starting compounds unsubstituted in the 2-position,especially the bicyclic 1,3-diketone starting compounds, are generallynot readily accessible and their derivatives can usually be preparedonly by means of a plurality of laborious synthesis steps andpurification procedures.

Furthermore, in the known processes the isolation of the end products,especially in the case of 2-benzoyl, 2-pyridycarbonyl and2-heteroarylcarbonyl derivatives, involves a generally multi-stepprocedure which is highly laborious. The purity and yield of the cyclic1,3-diketones prepared using the known processes are therefore oftenunsatisfactory.

The problem of the present invention is accordingly to make available anovel general process for the preparation of monocyclic and bicyclic1,3-diketone derivatives, especially 2-benzoyl, 2-isonicotinoyl and2-nicotinoyl derivatives, which makes it possible to prepare suchcompounds in high yields and good quality with a simple reactionprocedure and little outlay without the above-mentioned disadvantages ofthe known processes.

The present invention accordingly relates to a process for thepreparation of compounds of formula I

wherein

Y is an organic substituent which is so selected that the compound offormula I has a pK value of from 1 to 5;

A₁ is CR₁R₂;

A₂ is oxygen, C(O), SO₂ or (CR₃R₄)_(n);

n is 1 or 2;

A₃ is CR₅R₆;

R₁, R₂, R₃, R₄, R₅ and R₆ are each independently of the othersC₁-C₄alkyl which may be mono-, di- or tri-substituted by C₁-C₄alkoxy,halogen, hydroxy, cyano, hydroxycarbonyl, C₁-C₄alkoxycarbonyl,C₁-C₄alkylthio, C₁-C₄alkylsulfinyl, C₁-C₄alkylsulfonyl,C₁-C₄alkylcarbonyl, phenyl or by heteroaryl, it being possible for thephenyl and heteroaryl groups in turn to be mono-, di- or tri-substitutedby C₁-C₄alkoxy, halogen, hydroxy, cyano, hydroxycarbonyl,C₁-C₄alkoxycarbonyl, C₁-C₄alkylsulfonyl or by C₁-C₄haloalkyl, thesubstituents on the nitrogen in the heterocyclic ring being other thanhalogen; and/or R₁, R₂, R₃, R₄, R₅ and R₆ are each independently of theothers hydrogen, C₁-C₄alkoxy, halogen, hydroxy, cyano, hydroxycarbonyl,C₁-C₄alkoxycarbonyl, C₁-C₄alkylthio, C₁-C₄alkylsulfinyl,C₁-C₄alkylsulfonyl, C₁-C₄alkylcarbonyl, phenyl or heteroaryl, it beingpossible for the phenyl and heteroaryl groups in turn to be mono-, di-or tri-substituted by C₁-C₄alkoxy, halogen, hydroxy, cyano,hydroxycarbonyl, C₁-C₄alkoxycarbonyl, C₁-C₄alkylsulfonyl or byC₁-C₄haloalkyl, the substituents on the nitrogen in the heterocyclicring being other than halogen; and/or

R₁ and R₂ together form a 3- to 5-membered carbocyclic ring which may besubstituted by C₁-C₄alkyl and/or interrupted by oxygen, sulfur, S(O),SO₂, OC(O), NR₇ or by C(O); and/or

R₂ and R₄ together or R₂ and R₅ together form a C₁-C₃alkylene chainwhich may be interrupted by oxygen, sulfur, SO, SO₂, OC(O), NR₈ or byC(O); it being possible for that C₁-C₃alkylene chain in turn to besubstituted by C₁-C₄alkyl; and

R₇ and R₈ are each independently of the other C₁-C₄alkyl,C₁-C₄haloalkyl, C₁-C₄alkylsulfonyl, C₁-C₄alkylcarbonyl orC₁-C₄alkoxycarbonyl; in which process

a) a compound of formula II

wherein A₁, A₂ and A₃ are as defined for formula I, is reacted with abromine or chlorine source to form a compound of formula III

wherein A₁, A₂ and A₃ are as defined for formula I and X is chlorine orbromine;

b) that compound is reacted with water to form the compound of formulaIV

wherein A₁, A₂ and A₃ are as defined for formula I and X is chlorine orbromine;

c) that compound is converted, using a compound of formula V

M⁺-O⁻—C(O)—Y  (V),

wherein Y is as defined hereinbefore and M⁺ is the hydrogen cation or analkali metal ion, alkaline earth metal ion or ammonium ion, into thecompound of formula VI

wherein A₁, A₂, A₃ and Y are as defined for formula I, and

d) then that compound is treated with a cyanide source in the presenceof a base.

Y is especially an organic substituent which is so selected that thecompound of formula I has a pK value of from 2.5 to 4.5.

The organic substituent Y may be a substituent of any desired structureprovided that it remains substantially inert under the reactionconditions of the process according to the invention.

Y is preferably a mono-, di- or tri-substituted phenyl, pyridyl orheteroaryl group, especially a di- or tri-substituted phenyl group or adi-substituted 2-pyridyl or 3-pyridyl group; the substitution pattern ofthose groups being freely selectable provided that the groups remainsubstantially inert under the reaction conditions of the processaccording to the invention. Preference is given to phenyl, 3-pyridyl andheteroaryl groups which carry at least one substituent located, veryespecially, in the ortho position.

Especially advantageously, it is possible, using the process accordingto the invention, to prepare compounds of formula I wherein

Y is

wherein

A₄ is CRa₁ or ═N—(O)_(p);

p is 0 or 1;

Ra₁ is hydrogen, C₁-C₆alkyl, hydroxy, C₁-C₆alkoxy, C₁-C₆haloalkoxy,C₃-C₆alkenyloxy, C₃-C₆haloalkenyloxy, C₃-C₆alkynyloxy,C₁-C₄alkylcarbonyloxy, C₁-C₄alkylsulfonyloxy, phenylsulfonyloxy,C₁-C₆alkylthio, C₁-C₆alkylsulfinyl, C₁-C₆alkylsulfonyl, C₁-C₆alkylamino,di(C₁-C₆alkyl)amino, C₁-C₃alkoxy-C₁-C₃alkylamino,C₁-C₃alkoxy-C₁-C₃alkyl-N(C₁-C₃alkyl)-, C₁-C₄alkoxycarbonyl,C₁-C₆haloalkyl, formyl, cyano, halogen, phenyl or phenoxy, it beingpossible for the phenyl-containing groups in turn to be substituted byC₁-C₃alkyl, C₁-C₃haloalkyl, C₁-C₃alkoxy, C₁-C₃haloalkoxy, halogen, cyanoor by nitro;

or Ra₁ is a three- to ten-membered monocyclic or together with Ra₂ orRa₅ annellated bicyclic ring system which may be interrupted once or upto three times by heterocyclic substituents selected from oxygen,sulfur, S(O), SO₂, N(Ra₆), carbonyl and C(═NORa₇), the ring system,unless it is annellated, being bonded to the carbon atom of thesubstituent A₄ either directly or by way of a C₁-C₄alkylene,C₁-C₄alkenylene or C₂-C₄alkynylene bridge which may be interrupted byoxygen, —N(C₁-C₄alkyl)-, sulfur, sulfinyl or by sulfonyl, and the ringsystem may contain not more than 2 oxygen atoms and not more than twosulfur atoms, and the ring system may in turn be mono-, di- ortri-substituted by C₁-C₆alkyl, C₁-C₆haloalkyl, C₂-C₆alkenyl,C₂-C₆haloalkenyl, C₂-C₆alkynyl, C₂-C₆haloalkynyl, C₁-C₆alkoxy,C₁-C₆haloalkoxy, C₃-C₆alkenyloxy, C₃-C₆alkynyloxy, C₁-C₆alkylthio,C₁-C₆haloalkylthio-, C₃-C₆alkenylthio, C₃-C₆haloalkenylthio,C₃-C₆alkynylthio, C₁-C₄alkoxy-C₁-C₂alkylthio,C₁-C₄alkylcarbonyl-C₁-C₂alkylthio, C₁-C₄alkoxycarbonyl-C₁-C₂alkylthio,cyano-C₁-C₄alkylthio, C₁-C₆alkylsulfinyl, C₁-C₆haloalkylsulfinyl,C₁-C₆alkylsulfonyl, C₁-C₆haloalkylsulfonyl, aminosulfonyl,C₁-C₄alkylaminosulfonyl, di(C₁-C₄alkyl)aminosulfonyl,di(C₁-C₄alkyl)amino, halogen, cyano, nitro, phenyl, benzyloxy and/or bybenzylthio, and it being possible for the phenyl-containing groups inturn to be substituted on the phenyl ring by C₁-C₃alkyl, C₁-C₃haloalkyl,C₁-C₃alkoxy, C₁-C₃haloalkoxy, halogen, cyano or by nitro, andsubstituents on the nitrogen in the heterocyclic ring are other thanhalogen;

or Ra₁ is the group -X₅-X₇ or the group -X₆-X₅-X₇; wherein

X₅ is oxygen, —O(CO)—, —(CO)O—, —O(CO)O—, —N(C₁-C₄alkyl)-O—,—O—N(C₁-C₄alkyl)-, sulfur, sulfinyl, sulfonyl, —SO₂N(C₁-C₄alkyl)-,—N(C₁-C₄alkyl)SO₂—, —N(C₁-C₂alkoxy-C₁-C₂alkyl)SO₂— or —N(C₁-C₄alkyl)-;

X₆ is a C₁-C₆alkylene, C₃-C₆alkenylene or C₃-C₆alkynylene chain whichmay be mono- or poly-substituted by halogen or by X₈, the unsaturatedbonds of the chain not being bonded directly to the substituent X₅;

Ra₆ is hydrogen, C₁-C₄alkyl, C₁-C₄alkylthio-C₁-C₄alkylcarbonyl,C₁-C₄alkylsulfinyl-C₁-C₄alkylcarbonyl,C₁-C₄alkylsulfonyl-C₁-C₄alkylcarbonyl, C₁-C₄alkoxycarbonyl,C₁-C₄alkylcarbonyl, phenylcarbonyl or phenyl, it being possible for thephenyl groups in turn to be substituted by C₁-C₄alkyl, C₁-C₄haloalkyl,C₁-C₄alkoxy, C₁-C₄haloalkoxy, C₁-C₄alkylcarbonyl, C₁-C₄alkoxycarbonyl,C₁-C₄alkylamino, di(C₁-C₄alkyl)amino, C₁-C₄alkylthio,C₁-C₄alkylsulfinyl, C₁-C₄alkyl-SO₂, C₁-C₄alkyl-S(O)₂O,C₁-C₄haloalkylthio, C₁-C₄haloalkylsulfinyl, C₁-C₄haloalkyl-SO₂,C₁-C₄haloalkyl-S(O)₂O, C₁-C₄alkyl-S(O)₂NH,C₁-C₄alkyl-S(O)₂N(C₁-C₄alkyl)-, halogen, nitro or by cyano;

Ra₇ is hydrogen, C₁-C₄alkyl, C₃-C₄alkenyl, C₃-C₄alkynyl or benzyl;

Ra₂ is hydrogen, C₁-C₆alkyl, C₁-C₆haloalkyl, C₂-C₆alkenyl,C₂-C₆haloalkenyl; vinyl substituted by C₁-C₂alkoxycarbonyl or by phenyl;or C₂-C₆alkynyl, C₂-C₆haloalkynyl; or ethynyl substituted bytrimethylsilyl, hydroxy, C₁-C₆alkoxy, C₁-C₄alkoxycarbonyl or by phenyl;C₃-C₆allenyl, C₃-C₆cycloalkyl or halo- or C₁-C₃alkoxymethyl-substitutedC₃-C₆cycloalkyl; or C₁-C₆alkoxy, C₃-C₆alkenyloxy, C₃-C₆alkynyloxy,C₁-C₆haloalkoxy, C₃-C₆haloalkenyloxy, cyano-C₁-C₄alkoxy,C₁-C₄alkoxy-C₁-C₄alkoxy, C₁-C₄alkylthio-C₁-C₄alkoxy,C₁-C₄alkylsulfinyl-C₁-C₄alkoxy, C₁-C₄alkylsulfonyl-C₁-C₄alkoxy,C₁-C₄alkoxycarbonyl-C₁-C₄alkoxy, C₁-C₆alkylthio, C₁-C₆alkylsulfinyl,C₁-C₆alkylsulfonyl, C₁-C₆haloalkylthio, C₁-C₆haloalkylsulfinyl,C₁-C₆haloalkylsulfonyl, C₁-C₄alkoxycarbonyl-C₁-C₄alkylthio,C₁-C₄alkoxycarbonyl-C₁-C₄alkylsulfinyl,C₁-C₄alkoxycarbonyl-C₁-C₄alkylsulfonyl, C₁-C₆alkylamino,di(C₁-C₆-alkyl)amino, C₁-C₃alkoxy-C₁-C₃alkylamino,C₁-C₃alkoxy-C₁-C₃alkyl-N(C₁-C₃alkyl), C₁-C₆-alkylaminosulfonyl,di(C₁-C₆alkyl)aminosulfonyl, C₁-C₄alkylsulfonyloxy,C₁-C₄haloalkylsulfonyloxy, C₁-C₄alkylsulfonylamino,C₁-C₄alkylsulfonyl-N(C₁-C₄alkyl), cyano, carbamoyl, C₁-C₄alkoxycarbonyl,formyl, halogen, rhodano, amino, hydroxy-C₁-C₄alkyl,C₁-C₄alkoxy-C₁-C₄alkyl, C₁-C₄alkylthio-C₁-C₄alkyl,C₁-C₄alkylsulfinyl-C₁-C₄alkyl, C₁-C₄alkylsulfonyl-C₁-C₄alkyl,cyano-C₁-C₄alkyl, C₁-C₆alkylcarbonyloxy-C₁-C₄alkyl,C₁-C₄alkoxycarbonyl-C₁-C₄-alkyl, C₁-C₄alkoxycarbonyloxy-C₁-C₄alkyl,rhodano-C₁-C₄alkyl, phenyl-C₁-C₄alkyl, phenoxy-C₁-C₄alkyl,benzyloxy-C₁-C₄alkyl, benzoyloxy-C₁-C₄alkyl, (2-oxiranyl)-C₁-C₄alkyl,C₁-C₄-alkylamino-C₁-C₄alkyl, di(C₁-C₄alkyl)amino-C₁-C₄alkyl,C₁-C₁₂alkylthiocarbonyl-C₁-C₄alkyl or formyl-C₁-C₄alkyl, benzylthio,benzylsulfinyl, benzylsulfonyl, benzyloxy, benzyl, phenyl, phenoxy,phenylthio, phenylsulfinyl or phenylsulfonyl; it being possible for thephenyl-containing groups in turn to be substituted by C₁-C₃alkyl,C₁-C₃haloalkyl, C₁-C₃alkoxy, C₁-C₃haloalkoxy, halogen, cyano or bynitro; or

Ra₂ is a three- to ten-membered monocyclic or annellated bicyclic ringsystem which may be aromatic, saturated or partially saturated and maycontain from 1 to 4 hetero atoms selected from nitrogen, oxygen andsulfur, the ring system being bonded to the group Q₁ or Q₂ directly orby way of a C₁-C₄alkylene, C₁-C₄alkenylene or C₂-C₄alkynylene bridgewhich may be interrupted by oxygen, —N(C₁-C₄alkyl)-, sulfur, sulfinyl,sulfonyl or by carbonyl; and each ring system may contain not more than2 oxygen atoms and not more than two sulfur atoms, and the ring systemmay in turn be mono-, di- or tri-substituted by C₁-C₆alkyl,C₁-C₆haloalkyl, C₂-C₆alkenyl, C₂-C₆haloalkenyl, C₂-C₆alkynyl,C₂-C₆haloalkynyl, C₁-C₆alkoxy, C₁-C₆haloalkoxy, C₃-C₆alkenyloxy,C₃-C₆alkynyloxy, hydroxy, mercapto, C₁-C₆alkylthio, C₁-C₆haloalkylthio,C₃-C₆alkenylthio, C₃-C₆haloalkenylthio, C₃-C₆alkynylthio,C₁-C₄alkoxy-C₁-C₃alkylthio, C₁-C₄alkylcarbonyl-C₁-C₃alkylthio,C₁-C₄alkoxycarbonyl-C₁-C₃alkylthio, cyano-C₁-C₃alkylthio,C₁-C₆alkylsulfinyl, C₁-C₆haloalkylsulfinyl, C₁-C₆alkylsulfonyl,C₁-C₆haloalkylsulfonyl, aminosulfonyl, C₁-C₄alkylaminosulfonyl,di(C₁-C₄alkyl)aminosulfonyl, di(C₁-C₄alkyl)amino, halogen, cyano, nitro,phenyl and/or by benzylthio; it being possible for phenyl and benzylthioin turn to be substituted on the phenyl ring by C₁-C₃alkyl,C₁-C₃haloalkyl, C₁-C₃alkoxy, C₁-C₃haloalkoxy, halogen, cyano or bynitro, and substituents on the nitrogen in the heterocyclic ring areother than halogen; or

Ra₂ is the group -X₁-X₃ or the group -X₂-X₁-X₃; wherein

X₁ is oxygen, —O(CO)—, —(CO)O—, —O(CO)O—, —N(C₁-C₄alkyl)-O—,—O—N(C₁-C₄alkyl)-, thio, sulfinyl, sulfonyl, —SO₂N(C₁-C₄alkyl)-,—N(C₁-C₄alkyl)SO₂—, —N(C₁-C₂alkoxy-C₁-C₂alkyl)SO₂— or —N(C₁-C₄alkyl)-;

X₂ is a C₁-C₆alkylene, C₃-C₆alkenylene or C₃-C₆alkynylene chain whichmay be mono- or poly-substituted by halogen or by X₄, the unsaturatedbonds of the chain not being bonded directly to the substituent X₁;

X₃ and X₇ are each independently of the other a C₁-C₈alkyl, C₃-C₆alkenylor C₃-C₆alkynyl group which may be mono-, di- or tri-substituted byhalogen, hydroxy, amino, formyl, nitro, cyano, mercapto, carbamoyl,C₁-C₆alkoxy, C₁-C₆alkoxycarbonyl, C₂-C₆alkenyl, C₂-C₆haloalkenyl,C₂-C₆alkynyl, C₂-C₆haloalkynyl, C₃-C₆cycloalkyl or halo-substitutedC₃-C₆cycloalkyl; or by C₃-C₆alkenyloxy, C₃-C₆alkynyloxy,C₁-C₆haloalkoxy, C₃-C₆haloalkenyloxy, cyano-C₁-C₆-alkoxy,C₁-C₆alkoxy-C₁-C6alkoxy, C₁-C₆alkoxy-C₁-C₆alkoxy-C₁-C₆alkoxy,C₁-C₆alkylthio-C₁-C₆alkoxy, C₁-C₆alkylsulfinyl-C₁-C₆alkoxy,C₁-C₆alkylsulfonyl-C₁-C₆alkoxy, C₁-C₆alkoxycarbonyl-C₁-C₆alkoxy,C₁-C₆alkoxycarbonyl, C₁-C₆alkylcarbonyl, C₁-C₆alkylthio,C₁-C₆alkylsulfinyl, C₁-C₆alkylsulfonyl, C₁-C₆haloalkylthio,C₁-C₆haloalkylsulfinyl, C₁-C₆haloalkylsulfonyl; oxiranyl which may inturn be substituted by C₁-C₆alkyl; (3-oxetanyl)-oxy which may in turn besubstituted by C₁-C₆alkyl; benzyloxy, benzylthio, benzylsulfinyl,benzylsulfonyl, C₁-C₆alkylamino, di(C₁-C₆alkyl)amino,C₁-C₄alkyl-S(O)₂O—, di(C₁-C₄alkyl)aminosulfonyl, rhodano, phenyl,phenoxy, phenylthio, phenylsulfinyl or by phenylsulfonyl; and it beingpossible for the phenyl- or benzyl-containing groups in turn to besubstituted by one or more C₁-C₆alkyl, C₁-C₆haloalkyl, C₁-C₆alkoxy,C₁-C₆haloalkoxy, halogen, cyano, hydroxy or nitro groups; or

X₃ and X₇ are phenyl which may be mono- or poly-substituted byC₁-C₆alkyl, C₁-C₆haloalkyl, C₁-C₆alkoxy, C₁-C₆haloalkoxy, halogen,cyano, hydroxy or by nitro; or

X₃ and X₇ are each independently of the other C₃-C₆cycloalkyl,C₁-C₆alkoxy- or C₁-C₆alkyl-substituted C₃-C₆cycloalkyl, 3-oxetanyl orC₁-C₆alkyl-substituted 3-oxetanyl; or

X₃ and X₇ are each independently of the other a three- to ten-memberedmonocyclic or annellated bicyclic ring system which may be aromatic,saturated or partially saturated and may contain from 1 to 4 heteroatoms selected from nitrogen, oxygen and sulfur, the ring system beingbonded to the substituent X₁ or X₅ directly or by way of aC₁-C₄alkylene, C₂-C₄alkenylene, C₂-C₄alkynylene,—N(C₁-C₄alkyl)-C₁-C₄alkylene, —S(O)—C₁-C₄alkylene or —SO₂—C₁-C₄alkylenegroup, and each ring system may contain not more than 2 oxygen atoms.and not more than two sulfur atoms, and the ring system may in turn bemono-, di- or tri-substituted by C₁-C₆alkyl, C₁-C₆haloalkyl,C₂-C₆alkenyl, C₂-C₆haloalkenyl, C₂-C₆alkynyl, C₂-C₆haloalkynyl,C₁-C₆alkoxy, hydroxy, C₁-C₆haloalkoxy, C₃-C₆alkenyloxy, C₃-C₆alkynyloxy,mercapto, C₁-C₆alkylthio, C₁-C₆haloalkylthio, C₃-C₆alkenylthio,C₃-C₆haloalkenylthio, C₃-C₆-alkynylthio, C₁-C₃alkoxy-C₁-C₃alkylthio,C₁-C₄alkylcarbonyl-C₁-C₂alkylthio, C₁-C₄alkoxycarbonyl-C₁-C₂alkylthio,cyano-C₁-C₃alkylthio, C₁-C₆alkylsulfinyl, C₁-C₆haloalkylsulfinyl,C₁-C₆alkylsulfonyl, C₁-C₆haloalkylsulfonyl, aminosulfonyl,C₁-C₂alkylaminosulfonyl, di(C₁-C₂alkyl)aminosulfonyl,di(C₁-C₄alkyl)amino, C₁-C₆carbonylamino, halogen, cyano, nitro, phenyl,benzyloxy and/or by benzylthio, it being possible for the phenyl groupsin turn to be substituted on the phenyl ring by C₁-C₃alkyl,C₁-C₃haloalkyl, C₁-C₃alkoxy, C₁-C₃haloalkoxy, halogen, cyano or bynitro, and the substituents on the nitrogen in the heterocyclic ring areother than halogen; and

X₄ and X₈ are each independently of the other hydroxy, C₁-C₆alkoxy,(C₃-C₆cycloalkyl)oxy, C₁-C₆alkoxy-C₁-C₆alkoxy,C₁-C₆alkoxy-C₁-C₆alkoxy-C₁-C₆alkoxy or C₁-C₆alkylsulfonyloxy;

Ra₃ is hydrogen, C₁-C₆alkyl, C₁-C₆haloalkyl, C₂-C₆alkenyl,C₂-C₆haloalkenyl, C₂-C₆alkynyl, C₂-C₆haloalkynyl, C₃-C₆cycloalkyl,C₁-C₆alkoxy, C₁-C₆haloalkoxy, C₁-C₆alkylthio, C₁-C₆alkylsulfinyl,C₁-C₆alkylsulfonyl, C₁-C₆haloalkylthio, C₁-C₆haloalkylsulfinyl,C₁-C₆haloalkylsulfonyl, amino, C₁-C₆alkylamino, di(C₁-C₆alkyl)amino,C₁-C₄alkylsulfonyl-N(C₁-C₄alkyl)-, C₁-C₆alkylaminosulfonyl,di(C₁-C₆alkyl)aminosulfonyl, cyano, halogen, C₁-C₄alkoxy-C₁-C₄alkyl,C₁-C₄alkylthio-C₁-C₄alkyl, C₁-C₄alkylsulfinyl-C₁-C₄alkyl,C₁-C₄alkylsulfonyl-C₁-C₄alkyl, phenyl, phenylthio, phenylsulfinyl,phenylsulfonyl or phenoxy, it being possible for the phenyl groups inturn to be substituted by C₁-C₃alkyl, C₁-C₃haloalkyl, C₁-C₃alkoxy,C₁-C₃haloalkoxy, halogen, cyano or by nitro;

Ra₄ is hydrogen, C₁-C₆alkyl, hydroxy, C₁-C₆alkoxy, C₁-C₆haloalkoxy,C₃-C₆alkenyloxy, C₃-C₆haloalkenyloxy, C₃-C₆alkynyloxy,C₁-C₄alkylcarbonyloxy, C₁-C₄alkylsulfonyloxy, phenylsulfonyloxy,C₁-C₄alkylthio, C₁-C₄alkylsulfinyl, C₁-C₄alkylsulfonyl, C₁-C₄alkylamino,di(C₁-C₄alkyl)amino, C₁-C₄alkoxycarbonyl, C₁-C₄haloalkyl, formyl, cyano,halogen, phenyl or phenoxy; it being possible for the phenyl-containinggroups in turn to be substituted by C₁-C₃alkyl, C₁-C₃haloalkyl,C₁-C₃alkoxy, C₁-C₃haloalkoxy, halogen, cyano or by nitro; or

Ra₄ is a three- to ten-membered monocyclic or with Ra₃ or Ra₅ annellatedbicyclic ring system which may contain from 1 to 4 hetero atoms selectedfrom nitrogen, oxygen and sulfur, the ring system, unless it isannellated, being bonded to the group Q₁ or Q₂ either directly or by wayof a C₁-C₄alkylene, C₁-C₄alkenylene or C₂-C₄alkynylene bridge which maybe interrupted by oxygen, —N(C₁-C₄alkyl)-, sulfur, sulfinyl, sulfonyl orby carbonyl; and the ring system may contain not more than 2 oxygenatoms and not more than two sulfur atoms, and the ring system may inturn may be mono-, di- or tri-substituted by C₁-C₆alkyl, C₁-C₆haloalkyl,C₂-C₆alkenyl, C₂-C₆haloalkenyl, C₂-C₆alkynyl, C₂-C₆haloalkynyl,C₁-C₆alkoxy, C₁-C₆haloalkoxy, C₃-C₆alkenyloxy, C₃-C₆alkynyloxy,C₁-C₆alkylthio, C₁-C₆haloalkylthio, C₃-C₆alkenylthio,C₃-C₆haloalkenylthio, C₃-C₆alkynylthio, C₁-C₄alkoxy-C₁-C₂alkylthio,C₁-C₄alkylcarbonyl-C₁-C₂alkylthio, C₁-C₄alkoxycarbonyl-C₁-C₂alkylthio,cyano-C₁-C₄alkylthio, C₁-C₆alkylsulfinyl, C₁-C₆haloalkylsulfinyl,C₁-C₆alkylsulfonyl, C₁-C₆haloalkylsulfonyl, aminosulfonyl,C₁-C₄alkylaminosulfonyl, di(C₁-C₄alkyl)aminosulfonyl, amino,C₁-C₄alkylamino, di(C₁-C₄alkyl)amino, halogen, cyano, nitro, phenyland/or by benzylthio; it being possible for phenyl and benzylthio inturn to be substituted on the phenyl ring by C₁-C₃alkyl, C₁-C₃haloalkyl,C₁-C₃alkoxy, C₁-C₃haloalkoxy, halogen, cyano or by nitro, andsubstituents on the nitrogen in the heterocyclic ring are other thanhalogen;

Ra₅ is hydrogen, C₁-C₆alkyl, C₁-C₆haloalkyl, C₂-C₆alkenyl,C₂-C₆haloalkenyl, C₂-C₆alkynyl, C₂-C₆haloalkynyl, C₃-C₆cycloalkyl,C₁-C₆alkoxy, C₁-C₆haloalkoxy, C₁-C₆alkylthio, C₁-C₆alkylsulfinyl,C₁-C₆alkylsulfonyl, C₁-C₆haloalkylthio, C₁-C₆haloalkylsulfinyl,C₁-C₆haloalkylsulfonyl, C₁-C₆alkylsulfonyloxy, hydroxy, mercapto, amino,C₁-C₆alkylamino, di(C₁-C₆alkyl)amino, C₁-C₄alkylsulfonylamino,C₁-C₄alkylsulfonyl-N(C₁-C₄alkyl)-, C₁-C₆alkylaminosulfonyl,di(C₁-C₆alkyl)aminosulfonyl, cyano, halogen, C₁-C₄alkoxy-C₁-C₄alkyl,C₁-C₄alkylthio-C₁-C₄alkyl, C₁-C₄alkylsulfinyl-C₁-C₄alkyl,C₁-C₄alkylsulfonyl-C₁-C₄alkyl, triazolyl, phenyl, phenylthio,phenylsulfinyl, phenylsulfonyl or phenoxy; it being possible for thephenyl-containing groups to be substituted by C₁-C₃alkyl,C₁-C₃haloalkyl, C₁-C₃alkoxy, C₁-C₃haloalkoxy, halogen, cyano or bynitro; and agronomically acceptable salts/N-oxides/isomers/enantiomersof those compounds.

The alkyl groups appearing in the above substituent definitions may bestraight-chain or branched and are, for example, methyl, ethyl,n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl. Alkoxy,alkenyl and alkynyl radicals are derived from the mentioned alkylgroups. The alkenyl and alkynyl groups may be mono- or poly-unsaturated.Alkoxy is, for example, methoxy, ethoxy, propoxy, isopropoxy, n-butoxy,isobutoxy, sec-butoxy or tert-butoxy. Alkoxycarbonyl is, for example,methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl,n-butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl ortert-butoxycarbonyl; preferably methoxycarbonyl or ethoxycarbonyl.

Halogen is generally fluorine, chlorine, bromine or iodine. The sameapplies also to halogen in conjunction with other meanings, such ashaloalkyl or halophenyl. Haloalkyl groups having a chain length of from1 to 6 carbon atoms are, for example, fluoromethyl, difluoromethyl,chlorodifluoromethyl, trifluoromethyl, chloromethyl, dichloromethyl,trichloromethyl, 2,2,2-trifluoroethyl, 1-fluoroethyl, 2-fluoroethyl,2-chloroethyl, 2-fluoroprop-2-yl, pentafluoroethyl,1,1-difluoro-2,2,2-trichloroethyl, 2,2,3,3-tetrafluoroethyl and2,2,2-trichloroethyl, pentafluoroethyl, heptafluoro-n-propyl andperfluoro-n-hexyl.

Alkenyl and alkynyl groups may be mono- or poly-unsaturated, so thatalkyl, alkenyl and alkynyl chains having one or more double or triplebonds are also included. Alkenyl is, for example, vinyl, allyl,isobuten-3-yl, CH₂═CH—CH₂—CH═CH—, CH₂═CH—CH₂—CH₂—CH═CH— orCH₃—CH═CH—CH₂—CH═CH—. A preferred alkynyl is, for example, propargyl,and a preferred allenyl is CH₂═C═CH₂—.

An alkylene chain may also be substituted by one or more C₁-C₃alkylgroups, especially by methyl groups. Such alkylene chains and alkylenegroups are preferably unsubstituted. The same applies also to all groupscontaining C₃-C₆cycloalkyl, C₃-C₅oxacycloalkyl, C₃-C₅thiacycloalkyl,C₃-C₄dioxacycloalkyl, C₃-C₄dithiacycloalkyl or C₃-C₄oxathiacycloalkylwhich occur, for example, also as part of oxygen- and sulfur-containingheterocyclic ring systems of the radicals Ra₁ and Ra₂.

A C₁-C₄alkylene, C₁-C₄alkenylene or C₂-C₄alkynylene chain which may beinterrupted by oxygen, —N(C₁-C₄alkyl)-, sulfur, sulfinyl or by sulfonyl,or in X₂ or X₆ in the meaning of a C₁-C₆alkylene, C₃-C₆alkenylene orC₃-C₆alkynylene chain which may be mono- or poly-substituted by halogenor by X₄ or X₈, and wherein the unsaturated bonds of the chain are notbonded directly to the substituent X₁ or X₅, is to be understood asbeing, for example —CH₂—, —CH₂CH₂—, 13 CH₂CH₂CH₂—, —CH₂CH₂CH₂CH₂—,—CH(CH₃)—, —CH₂CH(CH₃)—, —CH₂CH(CH₃)CH₂—, —CH₂CH(Cl)CH₂—,—CH₂CH(OCH₃)CH₂—, —CH₂O—, —OCH₂—, —CH₂OCH₂—, —OCH₂CH₂—, —OCH₂CH₂CH₂—,—CH₂OCH₂CH₂—, —CH₂OCH(CH₃)CH₂—, —SCH₂—, —SCH₂CH₂—, —SCH₂CH₂CH₂—, —CH₂S—,—CH₂SCH₂—, —CH₂S(O)CH₂—, —CH₂SO₂CH₂—, —CH₂SCH₂CH₂—, —CH₂S(O)CH₂CH₂—,—CH₂SO₂CH₂CH₂—, —CH₂SO₂NH—, —CH₂N(CH₃)SO₂CH₂CH₂—, —N(SO₂Me)CH₂CH₂—,—CH₂C(O)NH— or —CH₂NHC(O)CH₂—. A C₂-C₄alkenylene chain which may beinterrupted by oxygen is accordingly to be understood as being, forexample, —CH═CH—CH₂—, —CH═CH—CH₂CH₂— or —CH═CHCH₂OCH₂—; and aC₂-C₄alkynylene chain which may be interrupted by oxygen is to beunderstood as being, for example, —C≡C—, —C≡CCH₂—, —C≡CCH₂O—,—C≡CCH₂OCH₂— or —OC≡CCH₂—.

A three- to ten-membered mono- or bi-cyclic ring system Ra₁ or Ra₂,which may be interrupted once or up to three times selected from oxygen,sulfur, S(O), SO₂, N(Ra₆), carbonyl and C(═NORa₇) and which is bonded tothe carbon atom of the substituent A₄ or to the group Q₁ or Q₂ eitherdirectly or by way of a C₁-C₄alkylene, C₁-C₄alkenylene orC₂-C₄alkynylene bridge which may be interrupted by oxygen,—N(C₁-C₄alkyl)-, sulfur, sulfinyl or by sulfonyl, is to be understood asbeing, for example, 1-methyl-1H-pyrazol-3-yl, 1-ethyl-1H-pyrazol-3-yl,1-propyl-1H-pyrazol-3-yl, 1H-pyrazol-3-yl, 1,5-dimethyl-1H-pyrazol-3-yl,4-chloro-1-methyl-1H-pyrazol-3-yl, 1H-pyrazol-1-yl,3-methyl-1H-pyrazol-1-yl, 3,5-dimethyl-1H-pyrazol-1-yl, 3-isoxazolyl,5-methyl-3-isoxazolyl, 3-methyl-5-isoxazolyl, 5-isoxazolyl,1H-pyrrol-2-yl, 1-methyl-1H-pyrrol-2-yl, 1H-pyrrol-1-yl,1-methyl-1H-pyrrol-3-yl, 2-furyl, 5-methyl-2-furyl, 3-furyl,5-methyl-2-thienyl, 2-thienyl, 3-thienyl, 1-methyl-1H-imidazol-2-yl,1H-imidazol-2-yl, 1-methyl-1H-imidazol-4-yl, 1-methyl-1H-imidazol-5-yl,4-methyl-2-oxazolyl, 5-methyl-2-oxazolyl, 2-oxazolyl,2-methyl-5-oxazolyl, 2-methyl-4-oxazolyl, 4-methyl-2-thiazolyl,5-methyl-2-thiazolyl, 2-thiazolyl, 2-methyl-5-thiazolyl,2-methyl-4-thiazolyl, 3-methyl-4-isothiazolyl, 3-methyl-5-isothiazolyl,5-methyl-3-isothiazolyl, 1-methyl-1H-1,2,3-triazol-4-yl,2-methyl-2H-1,2,3-triazol-4-yl, 4-methyl-2H-1,2,3-triazol-2-yl,1-methyl-1H-1,2,4-triazol-3-yl, 1,5-dimethyl-1H-1,2,4-triazol-3-yl,3-methyl-1H-1,2,4-triazol-1-yl, 5-methyl-1H-1,2,4-triazol-1-yl,4,5-dimethyl-4H-1,2,4-triazol-3-yl, 4-methyl-4H-1,2,4-triazol-3-yl,4H-1,2,4-triazol-4-yl, 5-methyl-1,2,3-oxadiazol-4-yl,1,2,3-oxadiazol-4-yl, 3-methyl-1,2,4-oxadiazol-5-yl,5-methyl-1,2,4-oxadiazol-3-yl, 4-methyl-3-furazanyl, 3-furazanyl,5-methyl-1,2,4-oxadiazol-2-yl, 5-methyl-1,2,3-thiadiazol-4-yl,1,2,3-thiadiazol-4-yl, 3-methyl-1,2,4-thiadiazol-5-yl,5-methyl-1,2,4-thiadiazol-3-yl, 4-methyl-1,2,5-thiadiazol-3-yl,5-methyl-1,3,4-thiadiazol-2-yl, 1-methyl-1H-tetrazol-5-yl,1H-tetrazol-5-yl, 5-methyl-1H-tetrazol-1-yl, 2-methyl-2H-tetrazol-5-yl,2-ethyl-2H-tetrazol-5-yl, 5-methyl-2H-tetrazol-2-yl, 2H-tetrazol-2-yl,2-pyridyl, 6-methyl-2-pyridyl, 4-pyridyl, 3-pyridyl,6-methyl-3-pyridazinyl, 5-methyl-3-pyridazinyl, 3-pyridazinyl,4,6-dimethyl-2-pyrimidinyl, 4-methyl-2-pyrimidinyl, 2-pyrimidinyl,2-methyl-4-pyrimidinyl, 2-chloro-4-pyrimidinyl,2,6-dimethyl-4-pyrimidinyl, 4-pyrimidinyl, 2-methyl-5-pyrimidinyl,6-methyl-2-pyrazinyl, 2-pyrazinyl, 4,6-dimethyl-1,3,5-triazin-2-yl,4,6-dichloro-1,3,5-triazin-2-yl, 1,3,5-triazin-2-yl,4-methyl-1,3,5-triazin-2-yl, 3-methyl-1,2,4-triazin-5-yl,3-methyl-1,2,4-triazin-6-yl,

wherein each R₂₆ is methyl, each R₂₇ independently is hydrogen,C₁-C₃alkyl, C₁-C₃alkoxy, C₁-C₃alkylthio or trifluoromethyl, and X₉ isoxygen or sulfur.

A further annellated (fused-on), monocyclic or bicyclic ring systemwhich is formed, for example, by two adjacent substituents Ra₁ and Ra₂or Ra₁ and Ra₅ and which is interrupted once or up to three timesselected from oxygen, sulfur, S(O), SO₂, —N(Ra₆)-, carbonyl andC(═NORa₇) and which may be additionally substituted by one or moresubstituents is to be understood as being, for example, an annellated,bidentate ring system of formula

wherein especially R₄₆ is hydrogen, halogen, C₁-C₄alkyl, C₁-C₄haloalkyl,C₁-C₄alkoxy or C₁-C₄alkylthio; R₄₇ is hydrogen, halogen, C₁-C₄alkyl orC₁-C₄alkoxy; R₅₀, R₅₁, R₅₂, R₅₃, R₅₄, R₅₅, R₅₆, R₅₇, R₅₈ and R₅₉ areeach independently of the others hydrogen or C₁-C₄alkyl; and X₁₀ isoxygen or NOR₅₉.

A heteroaryl group Y substituted at least in the ortho position is to beunderstood as being especially a 5- or 6-membered aromatic heteroarylgroup as defined hereinbefore which is, in addition, substituted once orup to three times by substituents selected from the meanings of Ra₁,Ra₂, Ra₃ and Ra₄ and Ra₅ at the nitrogen and/or at the carbon atoms.

Using the process according to the invention it is possible, especiallyadvantageously, to prepare the cyclohexanedione herbicides described inWO 00/15615, WO 00/37437, WO 01/66522 and WO 01/94339.

Compounds of formula I that are highly suitable for preparation usingthe process according to the invention are those wherein

R₁ and R₂ are hydrogen;

Q is Q₁, wherein A₄ is CRa₁ or N—(O)_(p);

p is 0;

Ra₁ is hydrogen, C₁-C₆alkyl, hydroxy, C₁-C₆alkoxy, C₁-C₆haloalkoxy,C₃-C₆alkenyloxy, C₃-C₆haloalkenyloxy, C₃-C₆alkynyloxy,C₁-C₄alkoxy-C₁-C₂alkoxy, C₁-C₄alkoxy-C₁-C₂alkoxy-C₁-C₂alkoxy,(C₃-C₆cycloalkyl)-C₁-C₂alkoxy, (1,3-dioxolan-2-yl)-C₁-C₂alkoxy,(tetrahydro-furan-2-yl)-C₁-C₂alkoxy, (tetrahydro-furan-3-yl)oxy,(oxetan-3-yl)oxy, (C₃-C₆cycloalkyl)oxy, C₁-C₄alkylsulfonyloxy,C₁-C₄alkylthio, C₁-C₄alkylsulfonyl, C₁-C₄alkylamino,di(C₁-C₄alkyl)amino, C₁-C₂alkoxyethylamino,C₁-C₂alkoxyethyl-(N-methyl)amino, morpholino,C₁-C₄alkylcarbonylaminoethoxy, C₁-C₄alkoxycarbonyl, hydroxymethyl,C₁-C₆alkoxymethyl, C₁-C₆haloalkoxymethyl, C₃-C₆alkenyloxymethyl,C₃-C₆haloalkenyloxymethyl, C₃-C₆alkynyloxymethyl,C₁-C₄alkoxy-C₁-C₂alkoxymethyl, (C₃-C₆cycloalkyl)methoxymethyl,(1,3-dioxolan-2-yl)-methoxymethyl, (tetrahydro-furan-2-yl)methoxymethyl,(tetrahydro-furan-3-yl)oxymethyl, (oxetan-3-yl)oxymethyl,(C₃-C₆cycloalkyl)oxymethyl, C₁-C₄alkylcarbonylamino-C₁-C₂alkoxy,C₁-C₄haloalkyl, cyano, halogen, phenyl or benzyloxy, it being possiblefor a phenyl-containing group in turn to be substituted by C₁-C₃alkyl,C₁-C₃haloalkyl, C₁-C₃alkoxy, C₁-C₃haloalkoxy, halogen, cyano or bynitro;

Ra₂ is C₁-C₆alkyl, C₁-C₆haloalkyl, C₂-C₆alkenyl, C₂-C₆haloalkenyl,C₂-C₆alkynyl, C₃-C₆-cycloalkyl, halo- or C₁-C₂alkoxymethyl-substitutedC₃-C₆cycloalkyl, C₁-C₆alkoxy, C₃-C₆-alkenyloxy, C₃-C₆alkynyloxy,C₁-C₆haloalkoxy, C₃-C₆haloalkenyloxy, C₁-C₄alkoxy-C₁-C₄-alkoxy,C₁-C₄alkylthio-C₁-C₄alkoxy, C₁-C₄alkylsulfinyl-C₁-C₄alkoxy,C₁-C₄alkylsulfonyl-C₁-C₄-alkoxy, C₁-C₄alkoxycarbonyl-C₁-C₄alkoxy,C₁-C₆alkylthio, C₁-C₆alkylsulfinyl, C₁-C₆alkylsulfonyl,C₁-C₆haloalkylthio, C₁-C₆haloalkylsulfinyl, C₁-C₆haloalkylsulfonyl,C₁-C₆alkylaminosulfonyl, di(C₁-C₆alkyl)aminosulfonyl,C₁-C₄alkylsulfonyloxy, C₁-C₄haloalkylsulfonyloxy,C₁-C₄alkylsulfonylamino, C₁-C₄alkylsulfonyl-N(C₁-C₄-alkyl), cyano,halogen, hydroxy-C₁-C₄-alkyl, C₁-C₄alkoxy-C₁-C₄alkyl,C₁-C₄alkylthio-C₁-C₄alkyl, C₁-C₄alkylsulfiny-C₁-C₄alkyl,C₁-C₄alkylsulfonyl-C₁-C₄alkyl, cyano-C₁-C₄alkyl,C₁-C₆alkylcarbonyloxy-C₁-C₄alkyl, C₁-C₄alkoxycarbonyl-C₁-C₄alkyl,C₁-C₄alkoxycarbonyloxy-C₁-C₄alkyl, phenoxy-C₁-C₄alkyl,benzyloxy-C₁-C₄alkyl, benzoyloxy-C₁-C₄alkyl, benzyloxy, benzylthio,phenoxy or phenylthio, it being possible for the phenyl-containinggroups in turn to be substituted by C₁-C₃alkyl, C₁-C₃haloalkyl,C₁-C₃alkoxy, C₁-C₃haloalkoxy, halogen, cyano or by nitro; or

Ra₂ is the group -X₁-X₃ or the group -X₂-X₁-X₃, wherein X₁, X₂ and X₃are as defined hereinbefore; or

Ra₃ is hydrogen; or

Ra₄ is hydrogen or methyl; or

Ra₅ is C₁-C₆haloalkyl, C₂-C₆haloalkenyl, C₁-C₆alkoxy, C₁-C₆haloalkoxy,C₁-C₆alkylthio, C₁-C₆alkylsulfinyl, C₁-C₆alkylsulfonyl,C₁-C₆haloalkylthio, C₁-C₆haloalkylsulfinyl, C₁-C₆haloalkylsulfonyl,C₁-C₆alkylsulfonyloxy, C₁-C₄alkylaminosulfonyl,di(C₁-C₄-alkyl)aminosulfonyl, C₁-C₄alkylsulfonylamino,C₁-C₄alkylsulfonyl-N(C₁-C₄alkyl)-, cyano, halogen, C₁-C₄alkoxymethyl,C₁-C₄alkylthiomethyl, C₁-C₄alkylsulfinylmethyl, C₁-C₄alkylsulfonylmethylor 1H-1,2,4-triazol-1-yl.

Compounds of formula I that are especially highly suitable forpreparation using the process according to the invention are thosewherein

R₂ and R₅ together are ethylene; (VI),

R₁ and R₆ are hydrogen;

A₂ is C(R₃R₄)_(n), wherein R₃ and R₄ are hydrogen and n is 1.

Reaction Step a):

Suitable bromine and chlorine sources are bromine, chlorine, theirsuccinimides such as N-bromosuccinimide (NBS), bromo- andchloro-acetamides and alkyl hypohalites. A preferred bromine source isbromine or NBS, and a preferred chlorine source is chlorine. In the caseof bromination it is advantageous for the HBr that is formed to beremoved from the reaction mixture, which may be accomplished, forexample, by introducing an inert gas such as, for example, argon ornitrogen, beneath the surface of the reaction mixture. Incorporation ofthe halogens into the reaction mixture can be carried out by dropwiseaddition or direct introduction beneath the surface of the reactionmixture. In the case of direct introduction, the halogens can be dilutedwith an inert gas such as, for example, argon or nitrogen.

The reaction according to Reaction Step a) is preferably carried out inthe presence of a free-radical initiator such as, for example, benzoylperoxide or azoisobutyronitrile. Illumination of the reaction mixtureis, moreover, advantageous. The halogenation is preferably carried outin the presence of azoisobutyronitrile.

The reaction is preferably carried out in the presence of a solvent.Suitable solvents are chlorobenzene, hexane, acetonitrile,tetrahydrofuran, methylcyclohexane or CCl₄ and also mixtures thereof;special preference is given to chlorobenzene or CCl₄.

The temperatures are generally from 0° C. to 150° C.; preference isgiven to a range from 80° C. to 130° C.

Compounds of formula II are known; they are commercially available insome cases or can be prepared by known methods.

The compounds of formula III

wherein A₁, A₂ and A₃ are as defined for formula I and X is eitherchlorine or bromine, are novel and were developed specifically for theprocess according to the invention, and the present inventionaccordingly also relates thereto. An especially valuable intermediate isthe compound of formula IIIb

Reaction Step b):

Reaction Step b) is preferably carried out with acid- or base-catalysis,preferably acid-catalysis. Suitable acids are mineral acids such assulfuric acid, hydrochloric acid or bromic acid or organic acids such asacetic acid. Special preference is given to sulfuric acid. As basesthere may be used organic or inorganic bases such as, for example,quaternary ammonium hydroxides or sodium hydroxide. For completeconversion at least 2 equivalents of water are used. In a preferredembodiment, first one equivalent of water is added to the compound offormula III until the monoketone of formula IV

wherein A₁, A₂ and A₃ are as defined hereinbefore and X is chlorine orbromine, is formed and then, as a result of the addition of the secondequivalent of water, the diketone of formula I is formed. Theselectivity of the reaction can be further increased using thispreferred embodiment.

Reaction Step c):

Reaction Step c) is carried out in the absence of water and in thepresence of a base, for example a tertiary amine, preferablytriethylamine or diisopropylethylamine. The reaction is preferablycarried out in the presence of a solvent such as a hydrocarbon,acetonitrile, ether or dipolar aprotic solvent, preferably in thepresence of acetonitrile, toluene, xylene or chlorobenzene, attemperatures of from 80° C. to 130° C.

Reaction Step d):

In an especially preferred embodiment of the process according to theinvention, the reaction according to Reaction Step d) is carried outwithout isolation of intermediates, that is to say the compound offormula VI obtained according to Reaction Step c) is treated in situwith cyanide ions in the presence of a base.

The cyanide ions are preferably used in amounts of from 0.01% to 15%.The reaction is preferably carried out at a temperature of from 50° C.to 150° C., especially at from 50° C. to 100° C., in the absence ofwater and in the presence of a base, for example from 0.1 to 2.5equivalents of triethylamine, or Hünig's base.

A suitable cyanide ion source is, for example, sodium cyanide, potassiumcyanide, copper(I) cyanide, acetone cyanohydrin or trimethylsilylcyanide, preferably potassium cyanide. Suitable solvents for ReactionStep c) are, for example, hydrocarbons, acetonitriles, ethers,chlorinated hydrocarbons and dipolar aprotic solvents. Such enol esterrearrangements are described, for example, in EP-A-0 186 117.

In a preferred embodiment of the process according to the invention,some reaction steps are carried out in the form of a one-pot reaction.Very special preference is given to carrying out Reaction Steps c) andd) in the form of a one-pot reaction. It can also be advantageous tocarry out the entire reaction (Reaction Steps a), b), c) and d)) in theform of a one-pot reaction, without isolation of intermediates. Thepossibility of carrying out the process according to the invention in aone-pot reaction constitutes a considerable advantage especially forlarge-scale application.

The process according to the invention will be explained in greaterdetail in the following Preparation Examples:

EXAMPLE P1 Preparation of 2,4,4-tribromo-bicyclo[3.2.1]oct-2-ene

To a solution of 15 g (88.9 mmol) of bicyclo[3.2.1]oct-2-ene in 250 mlof CCl₄ there are added, under a nitrogen atmosphere, 1.54 g (9.26 mmol)of azoisobutyronitrile. The reaction mixture is then illuminated with astrong lamp and heated to a temperature of 80° C., with stirring. 30 g(0.17 mol) of N-bromosuccinimide (NBS) are then added and stirring iscarried out for 1.25 hours at a temperature of 80° C. Then, at intervalsof about 1.5 hours, three further portions of 30 g (0.17 mol), 11.6 g(64.5 mmol) and 18.4 g (0.1 mol) of NBS are added and the reactionmixture is maintained at that temperature, with stirring, untilconversion is complete. The reaction mixture is then cooled to ambienttemperature and diluted with 100 ml of isohexane. After filtration andremoval of the solvent in vacuo, 43.2 g (52% of theory) of2,4,4-tribromo-bicyclo[3.2.1]oct-2-ene are obtained as a red-brown oil.

MS: 265 (M⁺-Br), 237, 183, 156, 119, 105, 89, 77, 63, 51, 39.

¹H NMR (CDCl₃): 1.55-1.65 (m, 1H), 1.85-2.20 (m, 4H), 2.55-2.60 (d, 1H),2.70-2.80 (d, 1H), 3.20 (d, 1H), 6.35 (s, 1H).

EXAMPLE P2 Preparation of 4-bromo-bicyclo[3.2.1]oct-3-en-2-one

To a solution of 89.9 g (7.9% w/w, 100%=7.1 g, 20.6 mmol) of2,4,4-tribromobicyclo[3.2.1]oct-2-ene in chlorobenzene there are added100 ml of acetonitrile and 100 ml of 10% sulfuric acid and stirring iscarried out for 50 minutes at ambient temperature. The pH is thenadjusted to 7 using aqueous sodium hydroxide solution and the aqueousphase is separated off. The organic phase is washed with 50 ml of waterand then dried using magnesium sulfate. After filtration and removal ofthe acetonitrile using a rotary evaporator, 57.8 g (88% of theory) of4-bromo-bicyclo[3.2.1]oct-3-en-2-one are obtained as a 6.3% solution inchlorobenzene.

MS: 200(M⁺), 172, 159, 146, 131, 121, 91, 77, 65, 51, 39.

¹H NMR (CDCl₃): 1.60-1.70 (m, 2H), 1.85-1.95 (m, 1H), 1.95-2.10 (m, 1H),2.10-2.25 (m, 2H), 2.95 (t, 1H), 3.20 (t, 1H), 6.20 (s, 1H).

EXAMPLE P3 Preparation of3-(2-nitro-4-methylsulfonyl-phenylcarbonyloxy)-cyclohex-2-en-1-one

To a mixture of 157 mg (1.15 mmol) of 3-chlorocyclohex-2-en-1-one(prepared as described in Synthesis (1974), (1), 47-8), 16 mg (0.12mmol) of ZnCl₂, 297 mg (1.15 mmol) of 2-nitro-4-methylsulfonylbenzoicacid and 3 ml of anhydrous acetonitrile there are added dropwise, undera nitrogen atmosphere, over the course of 15 minutes, 166 mg (1.27 mmol)of diisopropylethylamine. A further 2 ml of acetonitrile are then addedand the reaction mixture is maintained at a temperature of 45° C. for 18hours in an oil bath, with stirring. The reaction mixture is then heatedup again and maintained at reflux temperature for 40 hours. The reactionmixture is then brought to ambient temperature and the solvent isremoved in vacuo. 25 ml of dichloromethane and 0.35 g of 36%hydrochloric acid in 5 ml of water are then added and the phases areseparated. The organic phase is washed twice with 10 ml of water, driedusing magnesium sulfate and concentrated in vacuo. 197 mg of3-(2-nitro-4-methylsulfonyl-phenylcarbonyloxy)-cyclohex-2-en-1-one areobtained in the form of a brown oil.

¹H NMR (CDCl₃): 2.10-2.20 (m, 2H), 2.45-2.50 (m, 2H), 2.70-2.75 (m, 2H),3.20 (s, 3H, CH ₃SO₂), 6.10 (s, 1H, C═CH), 8.00 (d, 1H, ar. H), 8.35 (d,1H, ar. H), 8.65 (s, 1H, ar. H).

EXAMPLE P4 Preparation of3-(2-methoxyethoxymethyl-6-trifluoromethyl-pyridin-3-ylcarbonyloxy)-cyclohex-2-en-1-one

To a mixture of 157 mg (1.15 mmol) of 3-chlorocyclohex-2-en-1-one, 16 mg(0.12 mmol) of ZnCl₂, 324 mg (1.15 mmol) of2-methoxyethoxymethyl-6-trifluoromethylnicotinic acid (preparationdescribed in WO 2001094339) and 2 ml of toluene there are addeddropwise, under a nitrogen atmosphere, over the course of 15 minutes,166 mg (1.27 mmol) of diisopropylethylamine. A further 2 ml of tolueneare then added and the reaction mixture is maintained under moderatereflux for 18 hours in an oil bath, with stirring. The reaction mixtureis then brought to ambient temperature and 30 ml of dichloromethane and20 ml of water are added. The organic phase is separated off and washedtwice with 0.1M hydrochloric acid (20 ml) and twice with water (10 ml).After drying using magnesium sulfate and concentrating in vacuo, 226 mgof3-(2-methoxyethoxymethyl-6-trifluoromethyl-pyridin-3-ylcarbonyloxy)-cyclohex-2-en-1-oneare obtained in the form of an orange-brown oil.

MS: 373 (M⁺), 354, 328, 262, 230, 202, 187, 159, 139, 109, 95, 59, 45.

¹H NMR (CDCl₃): 2.10-2.20 (m, 2H), 2.45-2.50 (m, 2H), 2.70-2.75 (m, 2H),3.35 (s, 3H, CH ₃O), 3.50 (CH₂CH ₂O), 3.70 (OCH ₂CH₂), 5.00 (s, 2H, arCH₂), 6.10 (s, 1H, C═CH), 7.75 (d, 1H, ar. H), 8.30 (d, 1H, ar. H).

EXAMPLE P5 Preparation of4-(2-methoxyethoxymethyl-6-trifluoromethyl-pyridin-3-ylcarbonyloxy)-bicyclo[3.2.1]oct-3-en-2-one

A mixture of 200 mg (1.15 mmol) of 4-chlorobicyclo[3.2.1]oct-3-en-2-one,16 mg (0.12 mmol) of ZnCl₂, 324 mg (1.15 mmol) of2-methoxyethoxymethyl-6-trifluoromethylnicotinic acid, 166 mg (1.27mmol) of diisopropylethylamine and 5 ml of toluene is stirred at roomtemperature under a nitrogen atmosphere until a clear brown solutionhaving a white sediment is formed. With stirring, the reaction mixtureis then maintained under moderate reflux for 26 hours in an oil bath.The reaction mixture is then cooled to ambient temperature and 30 ml ofdichloromethane are added. The solution is then washed twice with water(20 ml each time), then twice with 0.1M hydrochloric acid (20 ml eachtime) and again twice with water (15 ml each time). After drying theorganic solution using magnesium sulfate and concentrating in vacuum,284 mg of4-(2-methoxyethoxymethyl-6-trifluoromethyl-pyridin-3-ylcarbonyloxy)-bicyclo[3.2.1]oct-3-en-2-oneare obtained in the form of a brown oil.

MS: 399 (M⁺), 380, 354, 262, 230, 204, 187, 159, 139, 121, 91.

¹H NMR (CDCl₃): 1.65-1.75 (m, 2H), 2.05-2.30 (m, 4H), 3.00 (br t, 1H),3.10 (br s, 1H), 3.35 (s, 3H, OCH ₃), 3.50 (m, 2H, CH₂CH ₂O), 3.70 (m,2H, OCH ₂CH₂), 5.00 (s, 2H, ar. CH ₂), 5.90 (s,1H. C═CH), 7.75 (d, 1H.ar. H), 8.30 (d, 1H. ar. H).

EXAMPLE P6 Preparation of4-(4-chlorophenyl-carbonyloxy)-bicyclo[3.2.1]oct-3-en-2-one

A mixture of 500 mg of 4-chlorobicyclo[3.2.1]oct-3-en-2-one, 440 mg ofZnCl₂, 400 mg of 4-chlorobenzoic acid, 1.05 g of diisopropylethylamineand 5 ml of toluene is stirred at room temperature under a nitrogenatmosphere at reflux temperature for 6 hours. After cooling, thereaction mixture is then diluted with dichloromethane and washed with 5%aqueous sulfuric acid and 5% aqueous sodium hydroxide. Afterconcentration of the organic phase to dryness by evaporation, 0.6 g of4-(4-chlorophenyl-carbonyloxy)-bicyclo[3.2.1]oct-3-en-2-one is obtained.

¹H NMR (CDCl₃): 1.65-1.8 (m, 2H), 2.0-2.4 (m, 4H), 2.95-3.1 (m, 2H,bridgehead), 5.85 (s, 1H, vinyl), 6.95-7.05 (m, 2H, aryl), 8.0-8.1 (m,2H, aryl).

EXAMPLE P7 Preparation of4-phenyl-carbonyloxy-bicyclo[3.2.1]oct-3-en-2-one

A mixture of 500 mg of 4-chlorobicyclo[3.2.1]oct-3-en-2-one, 440 mg ofZnCl₂, 400 mg of 4-benzoic acid, 1.05 g of diisopropylethylamine and 5ml of toluene is stirred at room temperature under a nitrogen atmosphereat reflux temperature for 8 hours. After cooling, the reaction mixtureis then diluted with dichloromethane and washed with 10% aqueoussulfuric acid. After concentration of the organic phase to dryness byevaporation, 0.4 g of 4-phenyl-carbonyloxy-bicyclo[3.2.1]oct-3-en-2-oneis obtained.

¹H NMR (CDCl₃): 1.65-1.8 (m, 2H), 2.0-2.4 (m, 4H), 2.95-3.1 (m, 2H,bridgehead), 5.85 (s, 1H, vinyl), 6.95-7.05 (m, 2H, aryl), 7.1-7.2 (m,1H, aryl), 8.05-8.15 (m, 2H, aryl).

EXAMPLE P8 Preparation of4-(2-methoxyethoxymethyl-6-trifluoromethyl-pyridin-3-ylcarbonyloxy)-bicyclo[3.2.1]oct-3-en-2-one

A mixture of 27 g of a 6.2% solution of4-bromobicyclo[3.2.1]oct-3-en-2-one in chlorobenzene, 110 mg of ZnCl₂,2.34 g of 2-methoxyethoxymethyl-6-trifluoromethylnicotinic acid and 1.2g of Hünig's base is stirred at room temperature under a nitrogenatmosphere until a dark-brown solution is formed. With stirring, thereaction mixture is then maintained under moderate reflux for 19 hoursin an oil bath. The mixture is then divided into 2 portions. To oneportion there are added a further 1.12 g of2-methoxyethoxymethyl-6-trifluoromethylnicotinic acid, 0.06 g of ZnCl₂and 0.6 g of Hünig's base. With stirring, the reaction mixture is thenmaintained under moderate reflux for 12 hours in an oil bath. Thesolution is then washed twice with 0.1M hydrochloric acid (20 ml eachtime) and twice with water (20 ml each time). After drying the organicsolution using magnesium sulfate and concentrating in vacuo, 3.9 g of4-(2-methoxyethoxymethyl-6-trifluoromethyl-pyridin-3-ylcarbonyloxy)-bicyclo[3.2.1]oct-3-en-2-oneare obtained in the form of a brown oil.

MS: 399 (M⁺), 380, 354, 262, 230, 202, 187, 159, 139, 121, 91.

¹H NMR (CDCl₃): 1.65-1.75 (m, 2H), 2.05-2.30 (m, 4H), 3.00 (br t, 1H),3.10 (br s, 1H), 3.35 (s, 3H, OCH ₃), 3.50 (m, 2H, CH₂CH ₂O), 3.70 (m,2H, OCH ₂CH₂), 5.00 (s, 2H, ar. CH ₂), 5.90 (s, 1H, C═CH), 7.75 (d, 1H,ar. H), 8.30 (d, 1H, ar. H).

EXAMPLE P9 Preparation of4-hydroxy-3-(2-methoxyethoxymethyl-6-trifluoromethyl-pyridin-3-ylcarbonyl)-bicyclo[3.2.1]oct-3-en-2-one

To a mixture of 200 mg (1.15 mmol) of4-chlorobicyclo[3.2.1]oct-3-en-2-one, 16 mg (0.12 mmol) of ZnCl₂, 324 mg(1.15 mmol) of 2-methoxyethoxymethyl-6-trifluoromethylnicotinic acid and2 ml of toluene there are added dropwise, under a nitrogen atmosphere,over the course of 15 minutes, 166 mg (1.27 mmol) ofdiisopropylethylamine. A further 2 ml of toluene are then added and thereaction mixture is maintained under moderate reflux for 23 hours in anoil bath, with stirring. The reaction mixture is then cooled to ambienttemperature, and 4 ml of acetonitrile, 2 drops of cyanohydrin, 465 mg oftriethylamine and a further 1 ml of acetonitrile are added. After dryingthe organic phase using magnesium sulfate and concentrating in vacuo,452 mg of4-hydroxy-3-(2-methoxyethoxymethyl-6-trifluoromethyl-pyridin-3-ylcarbonyl)-bicyclo[3.2.1]oct-3-en-2-oneare obtained in the form of a viscous oil.

MS: 399 (M⁺), 380, 356, 340, 310, 282, 256, 228, 202, 174, 152, 128, 67,45.

¹H NMR (CDCl₃): 1.70-1.80 (m, 2H), 2.05-2.30 (m, 4H), 2.90 (br s, 1H),3.15 (br s, 1H), 3.30 (s, 3H, OCH ₃), 3.40 (m, 2H, CH₂CH ₂O), 3.50 (m,2H, OCH _(b 2)CH₂), 4.75 (s, 2H, ar. CH ₂), 7.60 (s, 2H, ar. H).

1. A process for the preparation of a compound of formula I

wherein Y is an organic substituent which is so selected that the compound of formula I has a pK value of from 1 to 5; A₁ is CR₁R₂; A₂ is oxygen, C(O), SO₂ or (CR₃R₄)_(n); n is 1 or 2; A₃ is CR₅R₆; R₁, R₂, R₃, R₄, R₅ and R₆ are each independently of the others C₁-C₄alkyl which may be mono-, di- or tri-substituted by C₁-C₄alkoxy, halogen, hydroxy, cyano, hydroxycarbonyl, C₁-C₄alkoxycarbonyl, C₁-C₄alkylthio, C₁-C₄alkylsulfinyl, C₁-C₄alkylsulfonyl, C₁-C₄alkylcarbonyl, phenyl or by heteroaryl, it being possible for the phenyl and heteroaryl groups in turn to be mono-, di- or tri-substituted by C₁-C₄alkoxy, halogen, hydroxy, cyano, hydroxycarbonyl, C₁-C₄alkoxycarbonyl, C₁-C₄alkylsulfonyl or by C₁-C₄haloalkyl, the substituents on the nitrogen in the heterocyclic ring being other than halogen; and/or R₁, R₂, R₃, R₄, R₅ and R₆ are each independently of the others hydrogen, C₁-C₄alkoxy, halogen, hydroxy, cyano, hydroxycarbonyl, C₁-C₄alkoxycarbonyl, C₁-C₄alkylthio, C₁-C₄alkylsulfinyl, C₁-C₄alkylsulfonyl, C₁-C₄alkylcarbonyl, phenyl or heteroaryl, it being possible for the phenyl and heteroaryl groups in turn to be mono-, di- or tri-substituted by C₁-C₄alkoxy, halogen, hydroxy, cyano, hydroxycarbonyl, C₁-C₄alkoxycarbonyl, C₁-C₄alkylsulfonyl or by C₁-C₄haloalkyl, the substituents on the nitrogen in the heterocyclic ring being other than halogen; and/or R₁ and R₂ together form a 3- to 5-membered carbocyclic ring which may be substituted by C₁-C₄alkyl and/or interrupted by oxygen, sulfur, S(O), SO₂, OC(O), NR₇ or by C(O); and/or R₂ and R₄ together or R₂ and R₅ together form a C₁-C₃alkylene chain which may be interrupted by oxygen, sulfur, SO, SO₂, OC(O), NR₈ or by C(O); it being possible for that C₁-C₃alkylene chain in turn to be substituted by C₁-C₄alkyl; and R₇ and R₈ are each independently of the other C₁-C₄alkyl, C₁-C₄haloalkyl, C₁-C₄alkylsulfonyl, C₁-C₄alkylcarbonyl or C₁-C₄alkoxycarbonyl; in which process a) a compound of formula II

wherein A₁, A₂ and A₃ are as defined for formula I, is reacted with a bromine or chlorine source to form a compound of formula III

wherein A₁, A₂ and A₃ are as defined for formula I and X is chlorine or bromine; b) that compound is reacted with water to form the compound of formula IV

wherein A₁, A₂ and A₃ are as defined for formula I and X is chlorine or bromine; c) that compound is converted, using a compound of formula V M⁺-O⁻—C(O)—Y  (V), wherein Y is as defined hereinbefore and M⁺ is the hydrogen cation or an alkali metal ion, alkaline earth metal ion or ammonium ion, into the compound of formula VI

wherein A₁, A₂, A₃ and Y are as defined for formula I, and d) then that compound is treated with a cyanide source in the presence of a base.
 2. A compound of formula III

wherein A₁, A₂ and A₃ are as defined for formula I in claim 1 and X is either chlorine or bromine.
 3. The compound of formula IIIb 